Vitamin A

Question 1

What are the properties that Vitamin A brings?

Answer 1

1) Vision Health
2) Immune System Health (stimulates white blood cells)
3) Causes bone resorption (bone deconstruction)
4) Maintains healthy endothelial cells.
5) Regulates cell growth/differentiation for reproduction

Question 2

What essential protein compound does vitamin A form, and what is its function?

Answer 2

Vitamin A is an essential component of rhodopsin.

• The protein acts to absorb light in the eye receptors
• The protein also maintains function for the conjunctival membranes (tissue lining the inside of the eyelid and the sclera) and cornea

Question 3

What is the recommended intake for 14+ year olds for males/females, and what foods offer the highest dose of vitamin A?

Answer 3

The RDA is 900mcg in males and 700mcg in females

• 3 oz liver = 6582mcg
• 1 Sweet potato = 1403mcg
• 1/2 cup Spinach = 573mcg
• 1/2 cup (125g) Pumpkin = 350mcg
• 1 cup milk = 149mcg

Question 4

What are the potential health consequences of vitamin A deficiency?

Answer 4

• Risks of infection related to diarrhea and measles
• Xerophthalmia (dryness of the rhodopsin-related eye tissues, which creates inflammation/blindness)
• Dry skin/hair

Question 5

What are the two main forms of vitamin A?

Answer 5

1) preformed vitamin A (retinol, retinyl esters)
- animal products, fortified foods, and vitamin supplements
2) provitamin A carotenoids (ex. beta-carotene); this is converted to retinol
- found naturally in plant foods.

Question 6

What solubility is vitamin A, and how does it affect its properties?

Answer 6

Vitamin A is fat-soluble, meaning it can become toxic in excess amounts as it is stored in fats, rather than being excreted.

• Vision changes such as blurry sight
• Bone pain (bone resorption)
• Nausea and vomiting
• Dry skin
• Sensitivity to bright light like sunlight